Mock objects in JUnit - Interactive Code Practice

Practice - 5 Tasks

1fill in blank

easy

Complete the code to create a mock object using Mockito.

JUnit

MyService service = Mockito.[1](MyService.class);

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Anew

Bspy

Ccreate

Dmock

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'spy' instead of 'mock' creates a spy, not a pure mock.

Using 'new' is not a Mockito method.

Mockito.mock() creates a mock object of the given class.

2fill in blank

medium

Complete the code to stub the method 'getData' to return 'Hello' when called.

JUnit

Mockito.when(service.[1]()).thenReturn("Hello");

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AfetchData

BgetData

Cretrieve

Dcall

Attempts:

3 left

💡 Hint

Common Mistakes

Using a method name that does not exist in the service interface.

Forgetting to use Mockito.when() before thenReturn().

The method 'getData' is stubbed to return 'Hello' when called.

3fill in blank

hard

Fix the error in verifying that 'process' method was called once on the mock.

JUnit

Mockito.verify(service, Mockito.[1]()).process();

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AcalledOnce()

Bonce()

Ctimes(1)

DverifyOnce()

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'once()' instead of 'times(1)'.

Using 'calledOnce()' or 'verifyOnce()' which are invalid.

Mockito.times(1) verifies the method was called exactly once.

4fill in blank

hard

Fill both blanks to stub 'calculate' method to return 10 when called with argument 5.

JUnit

Mockito.when(service.[1]([2])).thenReturn(10);

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Acalculate

B5

C10

Dcompute

Attempts:

3 left

💡 Hint

Common Mistakes

Using wrong method name like 'compute'.

Using return value as argument.

The method 'calculate' is stubbed to return 10 when called with argument 5.

5fill in blank

hard

Fill all three blanks to verify 'update' method was called twice with argument 'data'.

JUnit

Mockito.verify(service, Mockito.[1]([2])).[3]("data");

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Atimes

B2

Cupdate

Donce

Attempts:

3 left

💡 Hint

Common Mistakes

Using 'once' instead of 'times' with 2.

Mixing method names or call counts.

Mockito.verify with times(2) checks 'update' was called twice with argument 'data'.